1. The document discusses the pathogenesis and diagnosis of acute bacterial sinusitis in children, including defining the typical bacterial causes, the role of prior viral infections in enabling bacterial overgrowth, and guidelines for diagnosing based on symptom duration and severity. 2. Imaging studies like CT scans are not recommended to distinguish between viral and bacterial infections but are recommended if complications like orbital or central nervous system issues are suspected. 3. The guidelines recommend prescribing antibiotics for severe or worsening cases but allow either antibiotics or additional observation for persistent cases lasting over 10 days without improvement.

1. Acute Bacterial Sinusitis
Rayan Hejazi, MBBS (with honor)

2. Outline
• Pathogenesis of acute bacterial sinusitis
• Clinical practice guideline for the diagnosis
and management of acute bacterial sinusitis in
children aged 1 to 18 years.
• Definitions
• Evidence quality

3. Pathogenesis of acute bacterial sinusitis
 Sinusitis is a common illness of childhood
and adolescence with significant acute and
chronic morbidity as well as the potentia for
serious complications. There are 2 types of
acute sinusitis viral and bacterial. The
common cold produces a viral, self- limited
rhinosinusitis.

4. Pathogenesis of acute bacterial sinusitis
 Acute bacterial sinusitis typically follows a
viral upper respiratory tract infection.
 Bacteria from the nasopharynx that enter
the sinuses are normally cleared readily,
but during viral rhinosinusitis, infamamation
and edema can block sinus drainage and
impair mucocili- ary clearance of bacteria.
The growth conditions are favorable, and
high titers of bacteria are produced.

5. Pathogenesis of acute bacterial sinusitis
 The bacterial pathogens causing acute
bacterial sinusitis in chil- dren and
adolescents include
 Streptococcus pneumoniae ( ~ 30%),
nontypable Haemophilus infuenzae ( ~
20%;), and Moraxella catarrhalis ( ~ 20%).
 Approximately 50% of H. infuenzae and
100% of M. catarrhalis are -lactamase
positive. About 25% of S. pneumoniae may
be penicillin resistant.

6. Pathogenesis of acute bacterial sinusitis
 Approximately 0.5-2% of viral upper
respiratory tract infections in children and
adolescents are complicated by acute
bacterial sinusitis.
 Some children with underlying predisposing
conditions have chronic sinus disease that
does not appear to be infectious. The
means for appropriate diagnosis and
optimal treatment of sinusitis remain
controversial.

7. Pathogenesis of acute bacterial sinusitis
 Both the ethmoidal and maxillary
sinuses are present at birth, but only the
ethmoidal sinuses are pneumatized ( Fig.
372-1 ). The maxillary sinuses are not
pneumatized until 4 yr of age. The
sphenoidal sinuses are present by 5 yr of
age, whereas the frontal sinuses begin
development at age 7-8 yr and are not
completely developed until adolescence.

8. Pathogenesis of acute bacterial sinusitis
 The ostia draining the sinuses are
narrow (1-3 mm) and drain into the
ostiomeatal complex in the middle meatus.
The paranasal sinuses are normally sterile,
main- tained by the mucociliary clearance
system.

9. Definitions
Statement Definition Implication
Strong
recommendation
A strong recommendation in favor of a particular action is made
when the anticipated benefits of the recommended intervention
clearly exceed the harms (as a strong recommendation against
an action is made when the anticipated harms clearly exceed the
benefits) and the quality of the supporting evidence is excellent.
In some clearly identified circumstances, strong
recommendations may be made when high-quality evidence is
impossible to obtain and the anticipated benefits strongly
outweigh the harms.
Clinicians should follow a
strong recommendation
unless a clear and
compelling rationale for an
alternative approach is
present.
Recommendation A recommendation in favor of a particular action is made when
the anticipated benefits exceed the harms but the quality of
evidence is not as strong. Again, in some clearly identified
circumstances, recommendations may be made when high-
quality evidence is impossible to obtain but the anticipated
benefits outweigh the harms.
Clinicians would be prudent
to follow a recommendation
but should remain alert to
new information and
sensitive to patient
preferences.
Option Options define courses that may be taken when either the quality
of evidence is suspect or carefully performed studies have shown
little clear advantage to 1 approach over another.
Clinicians should consider
the option in their decision-
making, and patient
preference may have a
substantial role.
No
recommendation
No recommendation indicates that there is a lack of pertinent
published evidence and that the anticipated balance of benefits
and harms is presently unclear.
Clinicians should be alert to
new published evidence that
clarifies the balance of
benefit versus harm.

10. Evidence Quality
Evidence Quality Preponderance of
Benefit or Harm
Balance of
Benefit and
Harm
A. Well-designed randomized controlled
trials (RCTs) or diagnostic studies on
relevant population
Strong
recommendation
Option
B. RCTs or diagnostic studies with minor
limitations; overwhelmingly consistent
evidence from observational studies
Recommendation/St
rong
Recommendation
C. Observational studies (case-control and
cohort design)
Recommendation
D. Expert opinion, case reports, reasoning
from first principles
Option No
Recommendatio
n
X. Exceptional situations where validating
studies cannot be performed and there is a
clear preponderance of benefit or harm
Recommendation/St
rong
Recommendation

11. Key Action Statement 1
• Clinician should make a presumptive diagnosis of acute bacterial sinusitis when a child with an acute upper
respiratory tract infection (URI) presents with the following:
• Persistent illness (i.e., nasal discharge [of any quality] or daytime cough or both lasting more than 10 days
without improvement)
• OR
• Worsening course (i.e., worsening or new onset of nasal discharge, daytime cough, or fever after initial
improvement)
• OR
• Severe onset (i.e., concurrent fever [temperature ≥39°C/102.2°F] and purulent nasal discharge for at least
3 consecutive days)
• (Evidence Quality: Grade B; Recommendation)

12. KAS Profile 1
• Aggregate evidence quality: B
• Benefit: Diagnosis allows decisions regarding management to be made. Children likely to benefit from antimicrobial therapy will be identified.
• Harm: Inappropriate diagnosis may lead to unnecessary treatment. A missed diagnosis may lead to persistent infection or complications.
• Cost: Inappropriate diagnosis may lead to unnecessary cost of antibiotics. A missed diagnosis leads to cost of persistent illness (loss of time from
school and work) or cost of caring for complications.
• Benefits-harm assessment: Preponderance of benefit
• Value judgments: None
• Role of patient preference: Limited
• Intentional vagueness: None
• Exclusions: Children aged <1 year or older than 18 years and with underlying conditions
• Strength: Recommendation

13. Key Action Statement 2.A
• Clinicians should not obtain imaging studies
(plain films, contrast-enhanced computed
tomography [CT], magnetic resonance imaging
[MRI], or ultrasonography) to distinguish acute
bacterial sinusitis from viral URI (Evidence
Quality: Grade B; Strong Recommendation).

14. KAS Profile 2A
• Aggregate evidence quality: B; overwhelmingly consistent evidence from observational studies
• Benefit: Avoids exposure to radiation and costs of studies. Avoids unnecessary therapy for false-positive diagnoses.
• Harm: None
• Cost: Avoids cost of imaging
• Benefits-harm assessment: Exclusive benefit
• Value judgments: Concern for unnecessary radiation and costs
• Role of patient preference: Limited. Parents may value a negative study and avoidance of antibiotics as worthy of radiation
but panel disagrees.
• Intentional vagueness: None
• Exclusions: Patients with complications of sinusitis
• Strength: Strong recommendation

15. Key Action Statement 2B
• Clinicians should obtain a contrast-enhanced
CT scan of the paranasal sinuses and/or an
MRI with contrast whenever a child is
suspected of having orbital or central nervous
system complications of acute bacterial
sinusitis (Evidence Quality: Grade B; Strong
Recommendation).

16. KAS Profile 2B
• Aggregate evidence quality: B; overwhelmingly consistent evidence from observational studies
• Benefit: Determine presence of abscesses, which may require surgical intervention; avoid sequelae because of appropriate
aggressive management.
• Harm: Exposure to ionizing radiation for CT scans; need for sedation for MRI
• Cost: Direct cost of studies
• Benefits-harm assessment: Preponderance of benefit
• Value judgments: Concern for significant complication that may be unrecognized and, therefore, not treated appropriately
• Role of patient preference: Limited
• Intentional vagueness: None
• Exclusions: None
• Strength: Strong recommendation

17. Key Action Statement 3.A
• Initial Management of Acute Bacterial Sinusitis
3A: "Severe onset and worsening course"
acute bacterial sinusitis. The clinician should
prescribe antibiotic therapy for acute bacterial
sinusitis in children with severe onset or
worsening course (signs, symptoms, or both)
(Evidence Quality: Grade B; Strong
Recommendation).

18. KAS Profile 3.A
• Aggregate evidence quality: B; randomized controlled trials
with limitations Benefit: Increase clinical cures, shorten illness
duration, and may prevent suppurative complications in a
high-risk patient population. Harm: Adverse effects of
antibiotics Cost: Direct cost of therapy Benefits-harm
assessment: Preponderance of benefit Value judgments:
Concern for morbidity and possible complications if untreated
Role of patient preference: Limited Intentional vagueness:
None Exclusions: None Strength: Strong recommendation

19. Key Action Statement 3.B
• 3B: "Persistent illness." The clinician should
either prescribe antibiotic therapy OR offer
additional outpatient observation for 3 days to
children with persistent illness (nasal
discharge of any quality or cough or both for
at least 10 days without evidence of
improvement) (Evidence Quality: Grade B;
Recommendation).

20. KAS Profile 3.B
• Aggregateevidence quality: B; randomizedcontrolledtrials with limitations Benefit: Antibiotics increase the chance of improvementor cure at 10 to 14 days (number needed to treat, 3–5); additional observationmay avoid the use of antibiotics with attendantcost and adverse effects. Harm:
Antibiotics have adverse effects (number needed to harm, 3) and may increase bacterialresistance. Observationmay prolong illness and delay start of needed antibiotictherapy. Cost: Directcost of antibiotics as well as cost of adverse reactions; indirectcosts of delayed recovery when observation is
used. Benefits-harmassessment: Preponderanceof benefit (because both antibiotictherapy and additionalobservation with rescue antibiotic, if needed, are appropriatemanagement). Value judgments: Role for additionalbrief observationperiod for selected childrenwith persistent illness sinusitis,
similarto what is recommendedfor acute otitis media, despite the lack of randomizedtrials specificallycomparingadditionalobservation with immediateantibiotictherapy and longer durationof illness before presentation.Role of patientpreference: Substantialrole in shared decision-makingthat
should incorporateillness severity, child's qualityof life, and caregiver values and concerns. Intentional vagueness: None Exclusions: Children who are excludedfrom randomizedclinicaltrials of acute bacterialsinusitis, as defined in the text Strength: Recommendation

21. Key Action Statement 4
• Clinicians should prescribe amoxicillin with or
without clavulanate as first-line treatment
when a decision has been made to initiate
antibiotic treatment of acute bacterial sinusitis
(Evidence Quality: Grade B;
Recommendation).

22. KAS Profile 4
• Aggregate evidence quality: B; randomized controlled trials with limitations Benefit: Increase
clinical cures with narrowest spectrum drug; stepwise increase in broadening spectrum as
risk factors for resistance increase Harm: Adverse effects of antibiotics including development
of hypersensitivity Cost: Direct cost of antibiotic therapy Benefits-harm assessment:
Preponderance of benefit Value judgments: Concerns for not encouraging resistance if
possible Role of patient preference: Potential for shared decision-making that should
incorporate the caregiver's experiences and values. Intentional vagueness: None Exclusions:
May include allergy or intolerance Strength: Recommendation

23. Key Action Statement 5.A
• Clinicians should reassess initial management
if there is either a caregiver report of
worsening (progression of initial
signs/symptoms or appearance of new
signs/symptoms) OR failure to improve (lack of
reduction in all presenting signs/symptoms)
within 72 hours of initial management
(Evidence Quality: Grade C;
Recommendation).

24. KAS Profile 5.A
• Aggregate evidence quality: C; observational studies Benefits: Identification of patients who may have been misdiagnosed, those at risk of
complications, and those who require a change in management Harm: Delay of up to 72 hours in changing therapy if patient fails to improve Cost:
Additional provider and caregiver time and resources Benefits-harm assessment: Preponderance of benefit Value judgments: Use of 72 hours to
assess progress may result in excessive classification as treatment failures if premature; emphasis on importance of worsening illness in defining
treatment failures. Role of patient preferences: Caregivers determine whether the severity of the patient's illness justifies the report to clinician of
the patient's worsening or failure to improve. Intentional vagueness: None Exclusions: Patients with severe illness, poor general health, complicated
sinusitis, immune deficiency, previous sinus surgery, or coexisting bacterial illness Strength: Recommendation

25. Key Action Statement 5.B
• If the diagnosis of acute bacterial sinusitis is
confirmed in a child with worsening symptoms
or failure to improve in 72 hours, then
clinicians may change the antibiotic therapy
for the child initially managed with antibiotic
OR initiate antibiotic treatment of the child
initially managed with observation (Evidence
Quality: Grade D; Option based on expert
opinion, case reports, and reasoning from first
principles).

26. KAS Profile 5.B
• Aggregate evidence quality: D; expert opinion and reasoning from first principles Benefit: Prevention of
complications, administration of effective therapy Harm: Adverse effects of secondary antibiotic therapy
Cost: Direct cost of medications, often substantial for second-line agents Benefits-harm assessment:
Preponderance of benefit Value judgments: Clinician must determine whether cost and adverse effects
associated with change in antibiotic is justified given the severity of illness. Role of patient preferences:
Limited in patients whose symptoms are severe or worsening but caregivers of mildly affected children
who are failing to improve may reasonably defer change in antibiotic. Intentional vagueness: None
Exclusions: None Strength: Option

27. Resources
• Read more at:
https://www.guidelinecentral.com/summaries
/clinical-practice-guideline-for-the-diagnosis-
and-management-of-acute-bacterial-sinusitis-
in-children-aged-1-to-18-years/#section-date
• Nelson Textbook of PEDIATRICS, 19 edition